Many pharmaceuticals, when administered to the body, causes, besides the beneficial effects, adverse effects, which at best is irritating to the treated patient but at worst leads to a damage that cannot be cured.
Several theories have been advanced to explain the mechanism by which substances such as drugs exert their negative side effects. The organs in the body and especially the cells are exposed to an environment where it is very essential that the levels of important constituents are balanced. Thus for the cell to work in a proper way the components of the cell membrane must be in correct order concerning for example lipid content, protein content, etc. In addition to this the signal transmission from extracellular mediators to intracellular events must have the possibilities to function properly.
An adverse disturbance of the function of an organ or a cell may be caused by a changed balance of minerals and metal ions. Many metals are necessary for the body, that is, they are essential for the proper function of proteins, such as enzymes and for signals mediating different metabolic properties. Furthermore metal ions are affecting the charge and pH of constituents of the cell membrane which are important for the function. However, in too high concentrations in certain parts of the body these metals can give harmful effects. This case is valid for instance for iron, copper, zinc, magnesium and calcium. In addition to this non-essential metals such as cadmium, lead and mercury, which are normally detoxified by certain proteins, can under certain circumstances be released to parts of the body where harmful effects may arise by interference with biologically important molecules.
An imbalance of e.g. iron or copper can in a medium of oxygen cause the formation of free radicals. These very reactive species can cause severe damages to cell membranes by so called lipid peroxidation. These processes disturb the normal activities of the cell.